In December, the weather in Castiglione del Lago is typically cold. Average daily high temperature in December is about 8 degrees above zero. On average, Castiglione del Lago has 13 sunny, 13 partly cloudy, and 5 rainy days in December. The rains are usually moderate. December as well as January, February, and November is considered the most uncomfortable time to visit Castiglione del Lago.